Question

Consider the balanced chemical equation that follows. You are asked to determine how many moles of water you can produce from 4.0 mol of hydrogen and excess oxygen. (Excess oxygen means that so much oxygen is available it will not run out.) Which of the numbers that appear in the balanced chemical equation below are used to perform this calculation?

2H2(g)+O2(g)→2H2O(l)

A. the coefficients for hydrogen and oxygen are used

B. the coefficients for water and hydrogen are used

C. the subscripts for water and hydrogen are used

Answer 1

Concepts and reason

The balanced chemical equation shows that the substances involved in a chemical reaction the substances that initially involved in a chemical reaction is called reactants and the substances that are produced are called products.

The excess reactant can be predicted by comparing the stoichiometric molar ratio of reactants and actual molar ratio.

After completing the reaction, the moles of excess reactant can be calculated by using the limiting reactant.

A coefficient is a simple whole number that is used to determine the relative number of moles or molecules in a chemical equation.

Fundamentals

Chemical equation:

The chemical equation is a symbolic representation for the chemical reaction. It must contain a reaction arrow that separates reactants and products.

Stoichiometry:

Stoichiometry is a quantitative relationship between the reactants and the products in a chemical equation.

Limiting reactant:

If the reactants do not react according to their stoichiometric ratios, one of the reactants is completely consumed during the completion of the reaction. This is the limiting reactant and the other reactant is in excess.

Mole:

Mole is a measure of the number of entities like atoms, molecules, or ions present in the substance. The mole of a substance always contains the same number of entities, independent of the substance. The number of entities in one mole is known as the Avogadro constant.

Indicate coefficients of each substance:

Hence, the options A and C are incorrect.

The correct option is B.

Ans:

The correct answer is shown below.